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troubleshoot network problems

Generally, I prefer to use nmap command for ICMP network scanning to probe all my network devices. By finding out unprotected devices you can improve network security and troubleshoot network problems. Recently, I discovered a cool utility called sing. It allows you to sends ICMP packets fully customized from command line. It allows you to do ICMP network scanning. Now you must be wondering, why perform ICMP network scanning? You can troubleshoot many network related problems without leaving your desk. For example,

  1. Find out using record route IP option to see the route that takes to vpn.nixcraft.in
  2. Find out remote server / network device operating system
  3. Diagnosing data-dependent problems in a network
  4. Test firewall security for invalid and garbage ICMP packets
  5. ICMP message types that generate responses from target routers / firewalls / IDS and other hosts
  6. Try to spoof router address and see how overall network reacts and many other things

This tool is not for a new UNIX / Linux user. It requires some sort of understanding for Internet hosts - communication layers and ICMP router discovery messages etc.
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